Annamalai et al. (3) studied the antimicrobial effects of 35 and 50 mM caprylic acid on Escherichia coli O157:H7 at 39°C in rumen fluid (pH 5.6 and 6.8) from 12 beef cattle. The results revealed that treatments with caprylic acid at both pH values significantly reduced E. coli O157:H7 cell numbers. At pH 5.6, both concentrations of caprylic acid killed E. coli O157:H7 rapidly, reducing the pathogen count to undetectable levels at 1 min of incubation (>6.0 log CFU/ml). However, the killing effect was reduced in buffered rumen fluid. At pH 6.8, 50 mM caprylic acid reduced the E. coli O157:H7 population to undetectable levels at 1 min of incubation, whereas 35 mM caprylic acid reduced the pathogen by approximately 3.0 and 5.0 log CFU/ml at 8 and 24 h of incubation, respectively